The medical marijuana industry in Colorado could face a new set of challenges tied to a highly controversial bill limiting the amount of THC drivers can have in their blood stream while behind the wheel.

The bill – which would allow police officers to convict drivers with more than 5 nanograms of THC per milliliter of blood in their systems – is up for debate in the Senate today and, if it passes, could be headed to the governor’s desk soon.

What would it mean for cannabis dispensaries and other medical marijuana businesses?

While it doesn’t directly affect them, it would have a significant impact on their clients and therefore the industry as a whole. Cannabis advocates warn that hundreds – or even thousands – of patients will back out of the state’s MMJ program as a result, which will shrink the overall market for medical marijuana and hurt the industry’s bottom line. The fear is that patients will shy away from medical marijuana because THC can stay in the blood stream for long periods, meaning drivers could be pulled over and charged even if they’re not high.

If enough patients give up their cannabis cards, some dispensaries will be forced to close. That, in turn, will ripple to other businesses that supply and support dispensaries.

But it might not be as dire as it seems. Some observers say that most patients will opt to keep their cards and just allow more time between when they use medical marijuana and when they drive.

Still, it’s yet another hurdle for an industry that faces immense challenges at every turn.

The MMJ industry was split on the THC driving limits. Several businesses and marijuana advocacy organizations – including the Medical Marijuana Industry Group, the Cannabis Business Association and Act4Colorado – said they would support setting limits as long as the amount of allowable marijuana was raised from the proposed 5 nanograms per milliliter of blood to 15 nanograms. But lawmakers shot down that idea last night, according to the Denver Post, saying that most drivers would be significantly impaired at that level.

Other MMJ professionals and marijuana advocates are adamantly opposed to any type of limits, saying there’s not way for patients to measure how much THC is in their system and that impairment levels vary greatly from person to person.

The nanogram test measures THC in blood; it DOES NOT measure impairment. The science just isn’t there. We should not be creating laws on shaky ground. The “per se” aspect of the bill would also make you AUTOMATICALLY GUILTY. You could not even defend yourself in court. For the “industry” groups to even support a 15ng bill is disgusting. Don’t harm the very people whose backs you built your business on.

is there one shred of evidence that drivers with 5, or even 15 ng of THC in their bloodstream are more dangerous than somebody on who’s on oxycodone or even caffeine? From the clinical trials I’ve read about, cannabis actually improves the scores of those ‘impaired’ by the herb; whereas, even a little bit of alcohol or caffeine has noticeably detrimental effects on safe driving… What’s it going to take for government to acknowledge the overwhelming evidence of this plant’s relative safety and efficacy compared to opiates and other ‘traditional’ drugs? A bunch of lawsuits clogging our already struggling court system and publicly humiliating these corrupt servants of medical tyranny ought to do the trick…